Clinical Conversations: Myasthenia Gravis – A Practical Approach for GPs | Part two

Clinical Conversations: Myasthenia Gravis – A Practical Approach for GPs | Part two


This article about myasthenia gravis highlights the central role GPs have in the diagnosis and ongoing management of patients with this rare condition. This is part two of a three-part article.

This is part two of this series.
Read Part 1 >>
Read Part 3 >>

Practice points

• The acetylcholine (ACH) receptor antibody is the most common antibody found.

• MuSK” stands for “muscle-specific kinase” antibody and it targets the postsynaptic neuromuscular junction.

• In patients with generalised clinical myasthenia, approximately 85% of them have ACH receptor antibodies and about 5% to 10% of them have MuSK antibodies.

• If there are pure ocular symptoms, half the patients have ACH receptor antibodies but MuSK antibodies are very rare.

• If antibodies have returned positive and a patient is waiting for a clinic appointment, a CT chest is something easily ordered prior to the patient being referred.

• If the patient is starting to aspirate or has a high respiratory rate, shortness of breath, head drop or swallowing difficulties they should be referred to Emergency.

• Pyridostigmine (Mestinon®) works almost immediately but it is limited in its maximal benefit. Patients take it fifteen to thirty minutes before any activity and may self-titrate the dose.

• Plasma exchange that directly removes the pathological antibodies, and intravenous immunoglobulins are prescribed via the blood bank. Both are expensive and short-acting.

• Long-acting oral treatments include corticosteroids, azathioprine, methotrexate, mycophenolate, and the infusions, such as rituximab and cyclophosphamide, but the latter are chemotherapy drugs.

• Acute, high dose steroids can severely exacerbate myasthenia gravis symptoms and cause them to go into cholinergic crisis requiring intubation.

We really have to be very careful of the patients who tell you that they’re feeling very tired or weak, or have visual disturbances that we cannot fully identify a single cause for, or weird swallowing difficulties… Now, having established that these signs are not that difficult to find, if you’ve got the right level of suspicion, how ...

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